diff --git a/.github/workflows/package.yml b/.github/workflows/package.yml
index 2022fbe..010a824 100644
--- a/.github/workflows/package.yml
+++ b/.github/workflows/package.yml
@@ -39,6 +39,7 @@ jobs:
       - uses: actions/checkout@v7
         with:
           persist-credentials: false
+          submodules: recursive
 
       - uses: actions/setup-dotnet@v6
         with:
@@ -74,6 +75,7 @@ jobs:
       - uses: actions/checkout@v7
         with:
           persist-credentials: false
+          submodules: recursive
 
       - uses: actions/setup-dotnet@v6
         with:
@@ -105,6 +107,7 @@ jobs:
       - uses: actions/checkout@v7
         with:
           persist-credentials: false
+          submodules: recursive
 
       # Wheel Wizard runs the downloaded setup with --version and refuses it when the reported
       # version differs from the release tag, so a tag that was pushed without bumping the pinned
diff --git a/.github/workflows/recomp-test.yml b/.github/workflows/recomp-test.yml
index 3a1244a..14a4797 100644
--- a/.github/workflows/recomp-test.yml
+++ b/.github/workflows/recomp-test.yml
@@ -16,6 +16,7 @@ jobs:
       - uses: actions/checkout@v7
         with:
           persist-credentials: false
+          submodules: recursive
 
       - uses: actions/setup-dotnet@v6
         with:
diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000..32950b1
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,3 @@
+[submodule "aurora-main"]
+	path = aurora-main
+	url = https://github.com/patchzyy/aurora.git
diff --git a/Launcher/Build-Installer.ps1 b/Launcher/Build-Installer.ps1
index 17f2b17..4469867 100644
--- a/Launcher/Build-Installer.ps1
+++ b/Launcher/Build-Installer.ps1
@@ -73,7 +73,16 @@ function Resolve-VcRuntimeDirectory([string]$RequestedPath) {
 function Copy-Directory([string]$Source, [string]$Destination) {
     Assert-Directory $Source "Source directory"
     [IO.Directory]::CreateDirectory($Destination) | Out-Null
-    Copy-Item -Path (Join-Path $Source '*') -Destination $Destination -Recurse -Force
+    # Source payloads are materialized trees, independent of Git checkout metadata.
+    foreach ($entry in Get-ChildItem -LiteralPath $Source -Force) {
+        if ($entry.Name -eq '.git') { continue }
+        $target = Join-Path $Destination $entry.Name
+        if ($entry.PSIsContainer) {
+            Copy-Directory $entry.FullName $target
+        } else {
+            Copy-Item -LiteralPath $entry.FullName -Destination $target -Force
+        }
+    }
 }
 function Compress-Zip([string]$Source, [string]$Destination, [string[]]$Entries) {
     $tar = Join-Path $env:SystemRoot 'System32\tar.exe'
diff --git a/Launcher/NativeBuildFlags.ps1 b/Launcher/NativeBuildFlags.ps1
index 7d88f4b..070604e 100644
--- a/Launcher/NativeBuildFlags.ps1
+++ b/Launcher/NativeBuildFlags.ps1
@@ -244,13 +244,14 @@ function Get-MkwAuroraSourceFingerprint([string]$AuroraDirectory) {
         (Join-Path $root 'extern') + '\',
         (Join-Path $root 'build') + '\'
     )
-    # Hidden files are skipped deliberately: Build-Installer.ps1 stages this tree
-    # with Copy-Item -Recurse (no -Force), so they never reach the payload and
-    # hashing them would make the two sides disagree by construction.
+    # Git metadata identifies a checkout location, not a source revision's bytes.
+    # Exclude it explicitly, including a submodule's non-hidden .git file.
     $files = Get-ChildItem -LiteralPath $root -Recurse -File |
         Where-Object {
             $full = $_.FullName
-            -not ($excludedPrefixes | Where-Object { $full.StartsWith($_, [StringComparison]::OrdinalIgnoreCase) })
+            $relative = $full.Substring($root.Length + 1).Replace('\', '/')
+            ($relative -notmatch '(^|/)\.git(/|$)') -and
+                -not ($excludedPrefixes | Where-Object { $full.StartsWith($_, [StringComparison]::OrdinalIgnoreCase) })
         } |
         Sort-Object { $_.FullName.Substring($root.Length + 1).Replace('\', '/') }
     $sha = [Security.Cryptography.SHA256]::Create()
diff --git a/Launcher/Prepare-Dependencies.ps1 b/Launcher/Prepare-Dependencies.ps1
index 18a8e9a..01996ae 100644
--- a/Launcher/Prepare-Dependencies.ps1
+++ b/Launcher/Prepare-Dependencies.ps1
@@ -21,6 +21,9 @@ $auroraExtern = Join-Path $repoRoot 'aurora-main\extern\CMakeLists.txt'
 $auroraDawn = Join-Path $repoRoot 'aurora-main\cmake\AuroraDawnProvider.cmake'
 $auroraLibUsb = Join-Path $repoRoot 'aurora-main\cmake\AuroraLibUSB.cmake'
 $auroraSdl = Join-Path $repoRoot 'aurora-main\cmake\AuroraSDL3Provider.cmake'
+if (-not (Test-Path -LiteralPath $auroraCMake -PathType Leaf)) {
+    throw 'Aurora sources are missing. Run git submodule update --init --recursive from the repository root first.'
+}
 
 # Name = directory under the destination; FetchContent maps it back through
 # FETCHCONTENT_SOURCE_DIR_<UPPERCASE NAME> (NativeBuildFlags.ps1), so the names are the declared
diff --git a/Launcher/Prepare-NativePrebuilt.sh b/Launcher/Prepare-NativePrebuilt.sh
index 7f31799..c5c9c6d 100755
--- a/Launcher/Prepare-NativePrebuilt.sh
+++ b/Launcher/Prepare-NativePrebuilt.sh
@@ -117,7 +117,7 @@ fingerprint_tree() {
     local root=$1; shift
     root=$(normalize "$root")
     [[ -d "$root" ]] || return 0
-    local find_args=("$root")
+    local find_args=("$root" -name .git -prune -o)
     local ex
     for ex in "$@"; do find_args+=(-path "$root/$ex" -prune -o); done
     find_args+=(-type f -print)
diff --git a/Launcher/Test-Recompilation.ps1 b/Launcher/Test-Recompilation.ps1
index 789e4dd..f30a77b 100644
--- a/Launcher/Test-Recompilation.ps1
+++ b/Launcher/Test-Recompilation.ps1
@@ -36,8 +36,17 @@ Write-Host "Synthetic recompilation workspace: $stage"
 
 # Copy current sources, including uncommitted edits, but no ignored build output.
 # An isolated workspace preserves the developer's real generated/ directory.
-$sourceFiles = & git -C $repoRoot -c core.quotepath=false ls-files --cached --others --exclude-standard -- runtime aurora-main
-if ($LASTEXITCODE -ne 0) { throw 'Could not enumerate runtime and Aurora sources.' }
+$auroraRoot = Join-Path $repoRoot 'aurora-main'
+if (-not (Test-Path -LiteralPath (Join-Path $auroraRoot '.git'))) {
+    throw 'Aurora submodule is not initialized. Run git submodule update --init --recursive first.'
+}
+# The parent tracks Aurora as one gitlink; enumerate its repository separately.
+# Retain untracked source files so local development edits are still tested.
+$sourceFiles = @(& git -C $repoRoot -c core.quotepath=false ls-files --cached --others --exclude-standard -- runtime)
+if ($LASTEXITCODE -ne 0) { throw 'Could not enumerate runtime sources.' }
+$auroraFiles = @(& git -C $auroraRoot -c core.quotepath=false ls-files --cached --others --exclude-standard)
+if ($LASTEXITCODE -ne 0) { throw 'Could not enumerate Aurora sources.' }
+$sourceFiles += @($auroraFiles | ForEach-Object { "aurora-main/$_" })
 foreach ($relative in $sourceFiles | Sort-Object -Unique) {
     $destination = Join-Path $stage $relative
     [IO.Directory]::CreateDirectory([IO.Path]::GetDirectoryName($destination)) | Out-Null
diff --git a/Launcher/build-appimage.sh b/Launcher/build-appimage.sh
index d8c0a76..afe2b13 100755
--- a/Launcher/build-appimage.sh
+++ b/Launcher/build-appimage.sh
@@ -167,6 +167,8 @@ echo "Staging the bundled workspace snapshot..."
 for dir in runtime aurora-main projects; do
     cp -r "$workspace/$dir" "$appdir/workspace/$dir"
 done
+# Ship source bytes, never submodule checkout pointers or embedded Git databases.
+find "$appdir/workspace" -name .git -prune -exec rm -rf {} +
 # Mirrors Build-Installer.ps1's own staging exclusions exactly: aurora-main/extern/CMakeLists.txt
 # is the real FetchContent driver and must ship, but any already-fetched dependency *subdirectory*
 # a developer's local checkout accumulated under extern/ is stale/large build output, not a
diff --git a/Launcher/macos/build-setup-pkg.command b/Launcher/macos/build-setup-pkg.command
index 50082c9..2c3f910 100755
--- a/Launcher/macos/build-setup-pkg.command
+++ b/Launcher/macos/build-setup-pkg.command
@@ -98,6 +98,8 @@ for source in aurora-main projects runtime translator; do
     [[ -d "$workspace/$source" ]] || fail "required workspace directory is missing: $source"
     copy_clean "$workspace/$source" "$resources/workspace/$source"
 done
+# Setup bundles contain materialized sources and must work without Git.
+find "$resources/workspace" -name .git -prune -exec rm -rf {} +
 mkdir -p "$resources/workspace/Launcher/macos"
 copy_clean "$workspace/Launcher/local-build-macos.command" "$resources/workspace/Launcher/local-build-macos.command"
 copy_clean "$workspace/Launcher/macos/extract-disc.command" "$resources/workspace/Launcher/macos/extract-disc.command"
diff --git a/runtime/CMakeLists.txt b/runtime/CMakeLists.txt
index 22537d3..d9bffb0 100644
--- a/runtime/CMakeLists.txt
+++ b/runtime/CMakeLists.txt
@@ -156,7 +156,14 @@ set(MKW_CPPWINRT_INCLUDE_DIR "" CACHE PATH "Optional self-contained C++/WinRT in
 # not compiled at all; imported targets with the same names are wired up from
 # the package instead, so this project's own code compiles and links exactly
 # as before.
-set(MKW_AURORA_DIR "${CMAKE_CURRENT_LIST_DIR}/../aurora-main")
+set(MKW_AURORA_DIR "${CMAKE_CURRENT_LIST_DIR}/../aurora-main" CACHE PATH
+    "Aurora source directory")
+if(NOT EXISTS "${MKW_AURORA_DIR}/CMakeLists.txt"
+        OR NOT EXISTS "${MKW_AURORA_DIR}/include/aurora/aurora.h")
+    message(FATAL_ERROR
+        "Aurora sources are missing at ${MKW_AURORA_DIR}. From the repository root, run "
+        "git submodule update --init --recursive, or set MKW_AURORA_DIR to an initialized Aurora checkout.")
+endif()
 
 # The translator's explicit float casts are PPC single-precision rounding points.
 # Fast-math may erase them and change guest-visible integer conversions.
@@ -171,9 +178,6 @@ if(MKW_NATIVE_PREBUILT_DIR)
     # not compiled here.
     include("${CMAKE_CURRENT_LIST_DIR}/cmake/NativePrebuilt.cmake")
 else()
-    if(NOT EXISTS ${MKW_AURORA_DIR}/CMakeLists.txt)
-        message(FATAL_ERROR "Requested aurora-main but ${MKW_AURORA_DIR} is missing")
-    endif()
     set(DAWN_ENABLE_D3D11 OFF CACHE BOOL "" FORCE)
     if(MKW_PLATFORM_WINDOWS)
         set(DAWN_ENABLE_D3D12 ON CACHE BOOL "" FORCE)
@@ -423,7 +427,7 @@ else()
         add_library(mkw_macos_native_compile OBJECT ${MKW_MACOS_NATIVE_AUDIT_SOURCES})
         target_include_directories(mkw_macos_native_compile PRIVATE
             "${CMAKE_CURRENT_LIST_DIR}/include" "${CMAKE_CURRENT_LIST_DIR}/src"
-            "${CMAKE_CURRENT_LIST_DIR}/.." "${CMAKE_CURRENT_LIST_DIR}/../aurora-main/include")
+            "${CMAKE_CURRENT_LIST_DIR}/.." "${MKW_AURORA_DIR}/include")
         target_compile_features(mkw_macos_native_compile PRIVATE cxx_std_20)
         target_compile_definitions(mkw_macos_native_compile PRIVATE SDL_MAIN_HANDLED TARGET_PC)
         target_link_libraries(mkw_macos_native_compile PRIVATE
diff --git a/runtime/cmake/PublicProducts.cmake b/runtime/cmake/PublicProducts.cmake
index e76e75a..2b7af0f 100644
--- a/runtime/cmake/PublicProducts.cmake
+++ b/runtime/cmake/PublicProducts.cmake
@@ -46,7 +46,7 @@ function(mkw_configure_object_target target)
         # Workspace root, so translator output is spelled "generated/<x>.h"
         # instead of a ../ chain whose depth depends on the includer.
         "${MKW_RUNTIME_SOURCE_DIR}/.."
-        "${MKW_RUNTIME_SOURCE_DIR}/../aurora-main/include")
+        "${MKW_AURORA_DIR}/include")
     target_compile_definitions(${target} PRIVATE
         TARGET_PC)
     set_target_properties(${target} PROPERTIES CXX_STANDARD 17 CXX_STANDARD_REQUIRED ON)
@@ -190,7 +190,7 @@ function(mkw_configure_product target)
         # Workspace root, so translator output is spelled "generated/<x>.h"
         # instead of a ../ chain whose depth depends on the includer.
         "${MKW_RUNTIME_SOURCE_DIR}/.."
-        "${MKW_RUNTIME_SOURCE_DIR}/../aurora-main/include")
+        "${MKW_AURORA_DIR}/include")
     target_compile_definitions(${target} PRIVATE
         SDL_MAIN_HANDLED _DISABLE_STRING_ANNOTATION _DISABLE_VECTOR_ANNOTATION TARGET_PC)
     target_compile_features(${target} PRIVATE cxx_std_20)